Crop Factor Demystified

As a photography enthusiast you’re surely heard the term crop factor. You may even have heard pro photographers talk about “35mm equivalent” or the lesser used “35mm focal length equivalent.” There are a few other related terms like crop sensor. If you’ve always wondered about crop factor and how it impacts your photography, this short video will demystify things:

Crop factor is directly influenced by sensor size. The larger the sensor, the smaller the crop factor. A lucid explanation would be that crop factor determines how much of the original 35mm frame the sensor in question is using.

The most significant impact of crop factor is on the field of view. Manufacturers routinely make lens mounts for smaller sensor cameras that are capable of using a lens designed for larger (full-frame) cameras. But smaller sensors don’t utilize the whole of the image coming through the lens.

Crop factor on APS-C cameras

With increased crop factor, the field of view is also reduced; and therein lies the importance of understanding this phenomenon. If you have a camera like the Nikon D7100 or a Canon 700D the field of view you get with a lens like the 50mm is much smaller than on a full-frame camera.

Different Cameras Have Different Crop Factors

Or rather, different mounts have different crop factors. Nikon’s DX format cameras, for example, have a crop factor of 1.5. Canon’s crop sensor cameras have a crop factor of 1.6. This number is an easy giveaway of the effective focal length or 35mm format equivalent focal length or the angle of view that you can expect from a particular lens.

Crop factor explained

Let’s say you’re using a 50mm lens designed for a full-frame camera on a crop sensor camera. If the camera is an EOS 700D or a 70D, the 35mm equivalent angle of view will be the same as an 80mm lens mounted on a full-frame camera. If it’s a Nikon D7100 or a D5300 the 35mm equivalent angle of view will be the same as a 75mm lens on a full-frame camera. If you own a 4/3 sensor camera, the crop factor in this case would be 2 (100mm).

What’s the Crop Factor on a Full-Frame Camera?

Crop factor on full-frame cameras

There’s no crop factor on a full-frame camera. But if you want to be finicky, the crop factor is 1 as it’s the standard by which all other sensors are measured.

Hopefully the above explanation cleared the mystery around crop factor. Do you have a preference for one size of sensor over another?

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